1. Field of the Invention
This invention relates to seaming of water-resistant materials and especially those intended for recreational fabric uses. While the ever growing interest in outdoor activities such as camping has resulted in significant improvements to base fabric materials used for campers, tents, garments and the like, the size or construction of articles used for these purposes frequently requires seaming of one or more component materials. The present invention is directed to methods for forming such seams and the resulting seamed materials.
2. Description of the Prior Art
The subject of seam sealing for recreational fabrics and the like has received considerable attention, and the solution to this persistent problem has been proposed in a number of forms. A common approach has been to apply a cover strip or tape of various materials over the seam after it has been formed. For example, U.S. Pat. No. 3,294,617 to Way dated Dec. 27, 1966, U.S. Pat. No. 3,246,621 to Copeland dated Apr. 19, 1966, U.S. Pat. No. 4,190,010 to Bibby dated Feb. 26, 1980, and U.S. Pat. No. 2,988,457 to Gatcomb dated June 13, 1961 teach varying embodiments of this concept. In addition, the use of sealing cement has been tried, and U.S. Pat. No. 4,305,414 to Bareis dated Dec. 15, 1981 is an example relating to this approach. In other cases reinforcing strips have also been taught as proving resistance to seam leakage and U.S. Pat. No. 3,328,854 to Tombari dated July 4, 1967 as well as U.S. Pat. No. 3,987,592 to Herminghaus and Jablonka dated Oct. 26, 1976 contain teachings of this type. It has also been proposed to bury the construction of the seam itself, so as to prevent or reduce seam leakage. U.S. Pat. No. 3,090,047 to de Grazia dated May 21, 1963 and U.S. Pat. No. 3,880,459 to Kelley dated Apr. 29, 1975 describe such seam constructions. In yet another approach, U.S. Pat. No. 4,416,027 to Perla dated Nov. 22, 1983, a filler strip is inserted by cutting abutting layers. Finally, it has been proposed to insert a strip of malleable rubber material in the stitching zone between the materials to be seamed. In U.S. Pat. No. 2,624,886 to Herman dated Jan. 13, 1953, such a seam is described; however, to achieve the desired result it is necessary to subject the sealed seam to pressure in order to force the tacky elastomer around the threads and seal the needle apertures. The tacky nature causes the elastomer to accumulate on needles producing frequent interruptions in stitching. Furthermore, the described elastomer tape is a rather complex multilayer laminate construction of vulcanized and unvulcanized rubber with a supporting layer. In spite of these many attempted improvements to achieve a waterproof seam for recreational and other types of fabrics, a completely satisfactory solution has not been identified as the serious recreational campers and manufacturers will know. Particularly with the newer, nonwoven fabric materials, the needle apertures caused by stitching remain sufficiently open to cause tents and the like to leak through the seamed areas particularly under prolonged, heavy rainy conditions. Thus, a need exists for further improvements which reduce or eliminate this seam leaking tendency.